Flow meter with adaptable beam characteristics

An embodiment provides a method for measuring a fluid parameter of fluid flowing in a channel, including: transmitting, using a transmitter of a device, directed energy carrying a signal toward a surface of a fluid in a fluid channel, so as to produce one or more reflections from the fluid surface; detecting, by at least one receiver of the device, one or more received signals associated with the one or more reflections so produced; and determining, based upon a measurement beam comprising characteristics of the transmitted and received signals, a fluid parameter to be measured using a processor of the device; wherein, a measurement beam characteristic is adjusted based on a distance from the device to the fluid surface. Other embodiments are described and claimed.